Recipes are for 1 cup Vanilla Buttercream Frosting. One drop is the size of a 4 mm round nail head. Gel paste will thicken after bottles are opened. If your gel paste comes out in drops larger than the 4 mm round nail head, count 1 large drop as 3 drops. We tested with AmeriColor Soft Gel Paste colors (from $1.35/color for a 3/4-oz. bottle). Because our formulas were tested with AmeriColor, we suggest using their products for results equal to our own. For a list of retailers, visit americolorcorp.com.